The location service is one of the characteristic mobile communication services, which has always been considered as a bright spot in the future mobile value-added service. Currently, the mobile location service has been opened by major mobile communication operators in such countries and zones as North America, Europe, Asia Pacific, Japan and Korea. The mobile location service is the most attractive service among the mobile value-added services, and is also one of the most complicated services in the industrial chain, in terms of the steps involved.
Location (LOC) is established in 2002 through combining the work of Location Interoperability Forum (LIF), location service in Wireless Application Protocol (WAP) forum and the related work of 3GPP R6 LCS stage3 by Open Mobile Architecture (OMA), with the purposes of establishing location service standards capable of interconnection and interworking; establishing specifications of mobile location services; ensuring end-to-end interoperability; gradually replacing the 3rd Generation Partnership Project (3GPP) and 3GPP2 in the areas of roaming and Le interfacing, and becoming a main international specification formulator in respect of location services. In view of the above, the major work of OMA LOC group is to establish a user-plane based location technology in the mobile communication network, to enable the transmission of the related location parameters via an IP path in the control plane location technology of mobile communication network and thus to realize location.
The Internet Engineering Task Force (IETF) was established in 1986, with the main tasks of research & development and establishment of technical specifications related to internet. At present, IETF has become a large technical research organization in the world and has the top authority in the internet industry. Teams in respect of the application field have been established in the IETF. Therefore, the protocols and standards regarding the application field related to location are developed and studied by the corresponding team. In the IETF, one of the standards related to location is Location Configuration Protocol (LCP) developed by the Geographic Location/Privacy (GEOPRIV) team. Location information can be provided, based on the LCP, in a form of location information value, or in a form of location information reference. The LCP comprises: Hypertext Transfer Protocol (HTTP) Enabled Location Delivery (HELD) standard, Dynamic Host Configuration Protocol (DHCP), Link Layer Discovery Protocol (LLDP), etc. Among them, the HELD standard is a protocol working at the seventh layer of the open hierarchical structure of Open System Interconnection (OSI), mainly describing how to obtain Location Information through the Location Generator in the access network.
Two approaches of obtaining the location information are defined in the HELD standard, i.e., obtaining by value or by reference, wherein obtaining by value means a terminal can directly request for location information from a location generator, the value can be, for example, in the form of text, similar to a civil address format; obtaining by reference means that the terminal can request for a location information Universal Resource Identifier (URI), or any other valid location information URI such as SIP URI, HTTP, HTTPS or the like, from the location generator. Because the location information URI is routable globally, the location information can be obtained through accessing to the location information URI. The two approaches above are compatible, and can be provided by the same location generator.
The HELD standard is a protocol based on Extensible Markup Language (XML), which can be bound to any session layer protocol, especially the session layer protocol with the function of Multipurpose Internet Mail Extensions (MIME), wherein binding to HTTP is a basic requirement. Meanwhile, the HELD standard is an extensible protocol working at the application layer, independent of the session layer.
The OMA LOC group has established the location standard based on secure user plane, i.e. Secure User Plane for Location (SUPL); the IETF has established the LCP standards. The HELD standard is the most typical standard of the LCP standards, enabling the location information transmission by means of HTTP on internet.
The OMA LOC group has completed the establishment of the SUPL 1.0 standard, which has been widely deployed and applied in the market. At present, the OMA LOC group is working on the establishment of the SUPL 2.0 standard, which is close to an end. In the SUPL 2.0 standard, the location functions in SUPL 1.0 standard have been enhanced, for example, triggering type location is added, location in different access networks is supported, etc. Meanwhile, different Global Navigation Satellite Systems (GNSS) are supported.
At present, the OMA LOC group is working on the establishment of technical specification of SUPL 3.0, which is at the first stage, i.e. the requirement gathering stage. At the present requirement gathering stage, it has been proposed to introduce the LCP is standard produced by the IETF into the SUPL architecture; however, there is still no scheme to meet such a demand currently.